The method of manufacturing a die used in manufacture of a magnetic disk is widely known. In this manufacturing method, nano particles are arrayed on a board. A liquid photo-curing polymer layer is formed on the board. The photo-curing polymer layer fills up gaps among nano particles. After the photo-curing polymer layer is cured, the board is peeled off from the photo-curing polymer layer. As a result, an array of dents carved by nano particles is formed on the surface of the photo-curing polymer layer. On the surface of the photo-curing polymer layer, a nickel plated film is formed. A die of nickel is then molded.
In such manufacturing methods, the liquid photo-curing polymer layer completely envelopes the nano particles. Therefore, in the transferred dents, the openings are narrowed. As a result, growth of the plated film is inhibited in the dents, and the plate film is not formed sufficiently. If the nickel plated film is formed in the dents, the plated film is left over in the dents after parting, and the surface shape of the photo-curing polymer layer is not transferred to the surface of plated film with sufficient precision.